Article by Kaushiki Das of Karimganj College
The world’s largest diamonds aren’t just more valuable for jewelers. They also holds surprising clues about the composition of the Earth’s mantle, says a new study.
A new study of the world’s largest diamond has shown that they are not only more valuable for jewelers but also of much value for geologist for offering a invaluable glimpse at the makeup of the Earth’s interior, hundreds of miles below the surface.
Led by the Gemological Institute of America (GIA) and published in the journal science, the study draw on a previous knowledge that larger diamonds are fundamentally different from their smaller counterparts in composition and structure, and explored how and where larger diamond form that causes to differ
“some of the world’s largest and most valuable diamonds like the culminant or the Lesotho promise, exhibit a distinct set of physical characteristics that have led many to regard them as separate from the others or more common diamonds” Wuyi Wang, director of GIA research and development and an author of the study said in a press release said “However, exactly how these diamonds form and where they tell us about the earth has remained a mystery until now”.
Diamonds are formed deep down the earth’s crust in the mantle and bought to the surface during volcanic eruptions, bringing with them tiny flakes of metal and mineral trapped inside, while these inclusions cut out to sell the jewel, they offer scientist a unique look at the composition of the earth’s interior.
Evan Smith, a diamond geologist of GIA and an author of the study, told NPR “Diamond is the ultimate Tupperware”.
The GIA procured eight finger-nail sized chunks of leftover diamond serapes, which the research team cut open and ground up to look at it using microscopes, lasers, magnets and electron-beams.
They found that the inclusion contained a mixture of iron, nickel, carbon and sulphur enclosed in a thin layer of liquid methane and hydrogen. The metallic inclusions indicated that the diamonds are formed under extreme pressure in oxygen deprived patches of liquid metal.
Furthermore, some samples also contained minerals inclusions that suggested the large diamonds from a much greater depth than smaller ones, as deep as 200 to 500 miles below the earth surface. Dr Smith told NPR, while smaller diamonds form at roughly 90 to 120 miles down.
The researchers say it if the pockets still exist, given the diamonds age. They range from 100 million years old to 1 billion years old.
But they also have a board geographic range having being fund on several continent, suggesting that the pockets are an important piece of geological history.